Blog Learn_the_effects_of_humidity_on_hvac_performance[1] | Air Comfort

High humidity outdoors and in your building can both negatively affect the cooling potential of your HVAC system. HVAC experts recommend a humidity level below 60% for your building to be comfortable, but that can be difficult to maintain as weather conditions change throughout the year. This brief article will summarize the HVAC problems high humidity can cause and the solutions that will reduce strain on your system and help keep your energy bills low.


Cold And Clammy

Central air conditioning units work by removing hot air from your building and blowing in fresh, refrigerated air. But that’s only half the battle. Central air conditioning also works to lower humidity levels to increase the efficiency of cooling efforts and make your building more comfortable. The air conditioning unit’s HVAC coil works to reduce humidity levels by condensing water vapor into liquid and then draining the excess. With proper unit sizing and installation, this system provides effective dehumidification in most conditions. But when humidity levels spike, however, most systems can’t cope. High humidity cancels out the air conditioner’s cooling effect. When the humidity is too high, your building will feel warmer than it is. You may find yourself running the air conditioner harder for longer and not getting the desired effects. You’ll know that the humidity in your building is too high if:

●       The air in your building feels moist.

●       There is a damp or musty smell in parts of your building.

●       Your windows are foggy.


Causes Of High Humidity With Air Conditioning Units

Oversized System – An oversized AC system does a poor job of controlling both temperature and humidity. That’s because the powerful compressor turns on and off too frequently, so the system never runs long enough to remove moisture from the air. You may need to install a smaller capacity AC system to fix this problem.

Single Speed – An air conditioner that’s only capable of running at one speed— basically, on or off—can have the same problems as one that’s too large when it comes to HVAC humidity control. When the unit can only run at one speed, it turns on and runs full blast until the air reaches set temperature. Then it turns off until the temperature once again goes above the thermostat threshold. That often means the unit doesn’t run consistently enough to remove humidity. Consider investing in an HVAC system that features variable speeds.

Negative Air Pressure – Negative air pressure results in too much air being vented from your ducts. This is usually the result of a poorly designed ventilation system. When you have negative pressure, the air tries to balance itself by drawing in more outside air any way that it can. So when the relative humidity outside gets into the 70’s, 80’s and above, all that muggy air is being drawn into the building. Changes to your ventilation system design may be needed to correct this issue.

Leaving The Fan On – The fan moves air even without the AC running, so you might feel like you’re getting some cooling benefit. But you’re making the humidity conditions worse. You can accidentally blow the moisture your AC has removed back into the space before it has a chance to drain away.

Old Unit – As your air conditioner ages, parts wear, and it may not run as efficiently as it used to. That tendency is increased when the system hasn’t been regularly maintained. In addition to inconsistent temperatures and inadequate cooling, you’ll start to notice poor HVAC humidity control. At this point, you may be facing a repair or replace decision.


Partner With Air Comfort: It’s All In The Name

If you find that your building is full of moist, musty air and foggy windows, it might be time to consider that your central air conditioning unit is failing to keep up with the dog days of summer. If your HVAC system needs adjustment, repair, or replacement, reach out to the team at Air Comfort.

Air Comfort Corporation is a full-service industrial and commercial HVAC provider specializing in a complete range of products and services, including comprehensive year-round preventive maintenance programs and emergency service, as well as design/build installation of equipment for new construction, and retrofits of existing mechanical systems.